Nerve Bournot Georges Le Palec Flow Field Measurement in a Crossflowing Elevated Jet

Structural features resulting from the interaction of a turbulent round jet issuing transversely into a uniform stream are described with the help of flow visualization and the PIV technique. The jet exits from a rigidly mounted pipe projecting at a distance from the floor of a tunnel. The aim of the present work is to investigate the flow structure in the near-field jet-pipe exit. Jet-to-crossflow velocity ratios from 0.375 to 3 were revealed at Reynolds numbers from 1660 to 6330. Flows in the vertical symmetry plane and horizontal plane across the jet-wake, jet-exit, and pipe-wake regions are investigated. The measured velocity fields present quantitative characteristics of the streamlines, vortices, and topological features of the flow structures. In particular, the origin and formation of the vortices in the wake are described and shown to be fundamentally different from the well-known phenomenon of vortex shedding from solid bluff bodies.